Radio frequency coil



Nov. 29, 1938. H E, THOMPSON 2,138,325@f RADIO FREQUENCY COIL Filed July 19, 1937 2 Sheets-Sheet l imm J4 nl il] 7 7 f f 32 37 66' 48 46 v 44 *H an? a 07746161277/ INVENTOR wn'nsss ATTORNEYS Nov. 29, 1938.

H. E. THOMPSON 2,138,330

RADIO FREQUENCY CO IL Filed July 19, 1937 2 Sheets-Sheet 2 WITNESS fzrarola E'. 17mm/030m INVENTOR f mgfwf@ ATTOR N EYS Patented Nov.l 29, 1938 UNITED lSTATES PATENT GFFICE ,4 Claims.

The object of the invention is to -provide a coil construction for use in connection with radio receivers that will be adapted for use with all wave bands; to provide a coil of the kind indicated in which the coil comprises a plurality of sections of windings of which one section is added to or subtracted ,from the other in adjusting the coil to the Vvarious frequencies within its range; tov

provide a coil operable in gangs and synchronously to effect the changes necessary for a selected frequency; and generally to provide a construction -of the kind indicated'which is of simple form, susceptible of cheap manufacture l andv of a character that will function eilectively 20 in the accompanying drawings but to which the invention is not to be restricted. Practical application may dictate certain changes or alterations v and the right is claimed to make any which fall within the spirit of the invention. In the drawings:

Figure 1 isvan elevational view of the improved coil.

Figure 2 is a bottom plan view. Figure 3 is a diagrammatlcal sectional view. Figure 4 is a top plan view, partly broken away. Figure 5 is a. diagrammatical view, showing the manner in which the sections of the coil are connected one to the other or sections which it is not desired to have function cut out, the setting of the parts in Figure 5 being for the lowest wave length within the range..

Figure 6 is a diagrammatical sectional view. of the coil alone, the switch cylinder being omitted.

Figure 7 is a sectional view on the plane indicated by the line 1--1 of Figure 6.

, Figure 8 is a detail perspective View ofthe clip employed on the switch cylinder.

Figure 9 is a view similar to Figure 8 but show ing the setting of the parts for the greatest wave length.

Figure 10 is a bottom plan view of a battery of a battery of coils, showing the means for adjusting them all simultaneously.

Figure 11 is a diagrammatical view showing the invention as it would be employed in a multistage radio frequency receiver. i

Whether the improved coil constituting the essential element of the invention be used singly or in combination, it is constructed with its windings -in section, the primary P consisting of the when in use and without likelihood of disarrangesections 20, 2|, 22 and 25 and the secondary S consisting of the sections 24, 25, 25 and 21. 'I'he sections are all wound on the insulating cylinder 28 which is preferably hollow and provided with rings 25 set in its ends which constitute bearings 5 for the switch cylinderl 50.

Each of the coil sections is connected to a pair of segments extending through the cylindrical wall oi the cylinder 28 but the segments for each coil section arerespectively in the planes 10 of the top and bottom convolutions of the section. Forexample, the coil 2| is connected with the segments 33 and 24; the coil 22 with the segments 35 and 36. The coil 23 has one terminal connected with the segment 31 while the other l terminal is carried to a suitable binding post 38 at the top of the cylinder 28 from which runs the section 39 for the antenna 40.

Short segments 4I are positioned in the planes of the segments 3l, 32, 34 and l5 and intervene between the segments 52 and I3, 24 and 35, and

t The coil sections of the secondary are similarly connected to the segments 43, 44, 45, 4E, 41, I8 25 'and 49, the remaining terminal of the coil section 24 being connected to a binding post 50 from which a lead 5I runs to the ground connection 52. Short segments 52, electrically interconnected as by a conductor 54, intervene be- 30 tween the segments 48 and 49, 46 and 41, and 44 and 45, with one in the plane of the segment 43. The section between the segments 53 continues by means of a conductor 54 to constitute the means forvconnection to the grid 55 of the 35 associated tube.

The coil segments, except the segments 4I and 53, as is apparent from Figures 5 and 9, are arranged ln groups o1' which the units of each group are of progressively increased angular extent, 40 segments of corresponding length being connected to adjacent terminals of adjacent coil sections.

In order that the coil sections may be connected one to the next, the switch cylinder 30 is provided. This is rotatably mounted in the rings 25 of the cylinder 28 and relative axial movement between the two cylinders is precluded by means of thrust pins 56. mounted in the cylinder 30 and positioned on opposite sides of one of the rings 29. The 50 cylinder is provided with sets of clips 51 extending through the wall and adapted for engagement with any of the segments connected with the coil sections. The clips are arranged in pairs in the planes of the coil section segments andthe units 55 ci' each pair are electrically connected by means of a bus bar 58.

The coil cylinder 24 is designed to be maintained in a stationary position and the relative movement between the two cylinders is effected by imparting turning movement to the cylinder 20. In one position, the clips will engage one of the segments 53 and the segment 4l, while another pair of clips will engage a segment 4| and the segment 3l. This position of the parts will connect the coil section 23 in the antenna. circuit and the coil section 24 in the grid circuit of the first radio frequency stage. This setting of the parts is for the shortest wave length. It the cylinder Il be turned further, the clips which previously engaged the segments I1 and 4l will remain in such engagement but the clips which engaged the segments 4| and 52 will be brought into engagement with the segments Il and 4|. But at this time the clips in the planes of the segments l5 and 41 will be brought into engagement with those segments and other segments of the groups comprislng the segments 4| and l2. In this arrangement the coils 22 and 23 will then be connected in the antenna and the coil sections 24 and 24 in the grid circuit, this setting being for the next wave length band. Further movement will connect in the coil sections 2| and 20 and still further movement the coil sections 20 and 21.

Whether the construction be employed in a tuned radio circuit, as indicated at Il in Figure 1i, or in a superheterodyne circuit, the adjustment of all of the coils is effected simultaneously. To this end, the cylinders 20 are designed to be rotated in synchronism by means of a drive shaft Sii which, at the point of location of each of the cylinders 28 is provided with worms 2i meshing with worm gear sectors I2 formed on rings carried by the projecting extremities of the cylinders 30. The shaft may be turned direct by an adjusting knob 62 or through the intervention of a gear couple 64, as shown, by means of which the knob shaft is operatively connected with the shaft S0. The knob shaft l! is mounted in appropriate bearings 66 while the shaft Il is mounted in bearings 61. A pointer 48 mounted to rotate with the knob may, by means of a dial carried on the face of the panel 88, indicate the setting of the coils for a selected wave length.

The invention having been described, what is claimed as new and useful is:

1. A radio frequency coil for a multiplicity of wave bands comprising a cylindrical form, a plurality of sections wound on said form, segments on the interior of said form with one connected to each of the extremities of said sections, the segments being arranged in pairs disposed in different planes with the units of each pair in a common plane, a cylindrical member within said form and angularly movable with respect thereto, and spaced clips carried by said member and arranged in pairs in the planes of the pairs of said segments for contacting with the segments upon relative angular movement of the member and form, the units of each pair of clips being electrically connected.

2. A radio frequency coil for a multiplicity of wave bands comprising a cylindrical form, a plurality of coil sections wound on said form, segments on the interior of said form with one connected to each of the extremities of said sections, the segments being arranged in pairs with successive pairs disposed in different planes, the segments of each pair being oi corresponding lengths but those of successive pairs being of progressively reduced length, a cylindrical member rotatably mounted in said form, clips carried by said member and arranged in pairs to engage said segments, the units of said pairs of clips being electrically interconnected.

3. A radio frequency coll for a multiplicity of wave bands comprising a cylindrical form, a plurality of coil sections wound on said form, segments on the interior of said form with one connected to each of the extremities of said sections, the segments being arranged in pairs with successive pairs disposed in diilerent planes, the` segments of each pair being of corresponding lengths but those of successive pairs being of progressively reduced length, a cylindrical member rotatably mounted in said form, clips carried by said member and arranged in pairs to engage said segments, the units of said pairs of clips being electrically interconnected, the said cylindrical member being provided with means for impartting turning movement to the same.

4. A radio frequency coil for a multiplicity of wave bands comprising a cylindrical form, a plurality of coil sections wound on said form, segments on the interior of said form with one connected to each of the extremities of said sections. the segments being arranged in pairs with successive pairs disposed in dinerent planes, the segments of each pair being of corresponding lengths but those of successive pairs being of progressively reduced length, a cylindrical member rotatably mounted in said form. clips carried by said member and arranged in pairs to engage said segments, the units of said pairs of clips being electrically interconnected, the said cylindrical member being provided with means for imparting turning movement to the same and consisting of a shaft, a worm carried by the shaft, and a worm gear carried by the cylindrical member and meshing with the worm.

HAROLD E. THOMISON. 

